1. Barton, A., 1955: "The concept of property space in social research ". In: Paul Lazarsfeld and Morris Rosenberg: The Language of social research . New-York: Free Press. French transl. in: R. Boudon, P. Lazarsfeld, 1971, third ed. Le vocabulaire des sciences sociales. Paris, La Haye: Mouton & co, pp. 148-170.
2. Bianchi, A.G., 1927: "Il pallonc e il tamburello". Evviva lo sport! Milano: Società anonima notari , pp. 128-135.